The present invention relates to a cordless telephone system and its independent base station and mobile station. More to particularly the present invention relates to a cordless telephone system and its independent base station and mobile station in which the mobile station is connected to a mobile communication network or a fixed network, and it is capable of executing radio communication both to outdoor public base station (hereinafter referring to public base station) in which original communication service control is executed, and to cordless telephone system independent base station (herein after referring to home independent base station) connected to the fixed network.